Implantable electronic devices

ABSTRACT

An implantable electronic device includes a flexible circuit board, one or more circuit components attached to the flexible circuit board and configured to convert electrical energy into electrical pulses, and one or more electrodes attached to the flexible circuit board without cables connecting the electrodes to each other or to the flexible circuit board, the one or more electrodes configured to apply the electrical pulses to a tissue adjacent the implantable electronic device.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of U.S. Provisional Application No.62/790,119, filed Jan. 9, 2019, and titled “Implantable ElectronicDevices,” which is incorporated by reference.

TECHNICAL FIELD

This disclosure relates to monolithic electronic devices designed to beimplanted within a patient's body for delivering electrical therapy totissues within the body.

BACKGROUND

Modulation of tissue within the body by electrical stimulation hasbecome an important type of therapy for treating chronic, disablingconditions, such as chronic pain, problems of movement initiation andcontrol, involuntary movements, dystonia, urinary and fecalincontinence, sexual difficulties, vascular insufficiency, and heartarrhythmia. For example, electrodes on an implantable tissue stimulatorcan be used to pass pulsatile electrical currents of controllablefrequency, pulse width, and amplitudes to a tissue. In many cases, suchelectrodes can experience mechanical failure at cables that connect theelectrodes to each other and to an adjacent circuit board. The cablescan render the tissue stimulator unsuitably stiff and, in some examples,the cables may pop off of the electrodes, break, fray, kink, orotherwise fail mechanically.

SUMMARY

In general, this disclosure relates to monolithic electronic devicesdesigned to be implanted within a patient's body for deliveringelectrical therapy to tissues within the body. Such electronic devicesinclude multiple electronic components secured to one small, flatsubstrate that can be delivered to the body through an introducerneedle.

In one aspect, an implantable electronic device includes a flexiblecircuit board, one or more circuit components attached to the flexiblecircuit board and configured to convert electrical energy intoelectrical pulses, and one or more electrodes attached to the flexiblecircuit board without cables connecting the electrodes to each other orto the flexible circuit board, the one or more electrodes configured toapply the electrical pulses to a tissue adjacent the implantableelectronic device.

Embodiments may provide one or more of the following features.

In some embodiments, the implantable electronic device further includesone or more joints at which the one or more electrodes are respectivelyattached to the flexible circuit board.

In some embodiments, the one or more joints include one or more ofstainless steel, platinum, platinum-iridium, gallium-nitride,titanium-nitride, and iridium-oxide.

In some embodiments, the one or more joints are part of the one or moreelectrodes.

In some embodiments, the one or more joints have a thickness of about0.05 mm to about 0.5 mm.

In some embodiments, the one or more electrodes are attached to theflexible circuit board respectively along one or more interior surfacesof the one or more electrodes.

In some embodiments, the one or more interior surfaces have a shape thatis complimentary to at least one or more portions of the one or morejoints.

In some embodiments, the one or more electrodes are attached to theflexible circuit board respectively along one or more exterior surfacesof the one or more electrodes.

In some embodiments, the one or more exterior surfaces have a shape thatis complimentary to at least one or more portions of the one or morejoints.

In some embodiments, the one or more electrodes are attached to theflexible circuit board in an automated manner.

In some embodiments, the one or more electrodes are attached to theflexible circuit board via laser welding, soldering, or conductive epoxyapplication.

In some embodiments, the one or more electrodes have a generally tubularshape. In some embodiments, the one or more electrodes are directlyattached to the flexible circuit board.

In some embodiments, the one or more electrodes are attached to theflexible circuit board within a compressive mechanical structure.

In some embodiments, the implantable electronic device further includesan antenna attached to the flexible circuit board and configured toreceive an input signal carrying the electrical energy.

In some embodiments, the antenna includes a layer of the flexiblecircuit board.

In some embodiments, the antenna is oriented parallel to the one or morecircuits.

In some embodiments, the antenna is oriented perpendicular to the one ormore circuits.

In some embodiments, the antenna includes two separate portions.

In some embodiments, the implantable electronic device is sized to bepassed through an introducer needle.

DESCRIPTION OF DRAWINGS

FIG. 1 is a top view of an electronic device.

FIG. 2 is a top view of the electronic device of FIG. 1, with electrodesomitted for illustration of underlying components.

FIG. 3 is a side view of the electronic device of FIG. 1, withelectrodes omitted for illustration of underlying components.

FIG. 4 is a side cross-sectional view of the electronic device of FIG.1, with a circuit board attached to electrodes along interior surfacesof the electrodes.

FIG. 5 illustrates various techniques by which the electrodes of theelectronic device of FIG. 1 can be attached to the flexible circuitboard of the electronic device, including laser welding, soldering, andconductive epoxy application.

FIG. 6 is a side cross-sectional view of an electronic device, with acircuit board attached to electrodes along exterior surfaces of theelectrodes.

FIG. 7 illustrates side cross-sectional views of electronic devicesincluding joints with non-circular cross-sectional shapes and with acircuit board attached to electrodes along interior surfaces of theelectrodes.

FIG. 8 illustrates side cross-sectional views of electronic devicesincluding joints with non-circular cross-sectional shapes and with acircuit board attached to electrodes along exterior surfaces of theelectrodes.

FIG. 9 is a side cross-sectional view of an electronic device thatincludes electrodes secured to a circuit board with a compressivemechanical structure.

FIG. 10 is a side cross-sectional view of an electronic device thatincludes electrodes secured to a circuit board with a compressivemechanical structure.

FIG. 11 is a top view of an electronic device.

FIG. 12 is a top view of the electronic device of FIG. 11, withelectrodes omitted for illustration of underlying components.

FIG. 13 is a side view of the electronic device of FIG. 11, withelectrodes omitted for illustration of underlying components.

FIG. 14 is a top view of an electronic device.

FIG. 15 is a top view of the electronic device of FIG. 14, withelectrodes omitted for illustration of underlying components.

FIG. 16 is a side view of the electronic device of FIG. 14, withelectrodes omitted for illustration of underlying components.

FIG. 17 is a top view of an electronic device including an antennaoriented parallel to circuit components of the electronic device.

FIG. 18 is a top view of an electronic device including an antennaoriented perpendicular to circuit components of the electronic device.

FIG. 19 is a side view of the electronic device of FIG. 18.

FIG. 20 is a top view of an electronic device including electrodecontact sites positioned on both ends of a circuit board.

FIG. 21 is a top view of an electronic device including an antennaformed from two separate portions.

FIG. 22 is a top view of an electronic device including an antennaformed from two separate portions.

FIG. 23 is a system block diagram of a tissue stimulator systemincluding the electronic device of FIG. 1.

FIG. 24 is a detailed block diagram of the tissue stimulator system ofFIG. 23.

DETAILED DESCRIPTION

FIGS. 1-3 illustrate various views of an electronic device 100 designedto be implanted within a patient's body for delivering electricaltherapy to tissues within the body. For example, the electronic device100 may be provided within a housing of a tissue stimulator or connectedto a tissue stimulator. The electronic device 100 is a monolithic devicefor which electronic components are secured to one small, flat substratethat can be delivered to the body through an introducer needle. Theelectronic device 100 includes a circuit board 102 and various circuitcomponents 104, an antenna 106, and electrodes 108 that are secured tothe circuit board 102. The electronic device 100 further includesmultiple pads 110 at which the electrodes 108 are respectively attachedto the circuit board 102.

The circuit board 102 is a flexible substrate including multiple layers112 in which the antenna 106 is interposed. The circuit board 102defines contact sites 114 that locate the pads 110 and typically has alength of about 0.5 mm to about 4 mm, a width of about 0.05 mm to about0.5 mm, and a thickness of about 0.0125 mm to about 0.5 mm. The circuitboard 102 is typically made of a dielectric substrate, such aspolyimide. In some embodiments, additional dielectric materials may beapplied to the circuit board 102 along certain regions for stiffening.

The circuit components 104 are distributed along the length of thecircuit board 102 and may be secured to the circuit board 102 viasolder, solder paste, or conductive epoxy. Example circuit components104 include diodes, capacitors, resistors, semiconductors, and otherelectromechanical components. The antenna 106 is integrated directlyinto one of the layers 112 of the circuit board and is designed toreceive an input signal carrying electrical energy that can be used bythe circuit components 104 and relayed to the electrodes 108 so that theelectrodes 108 can apply one or more electrical pulses to adjacenttissue. Arrangement of the antenna 106 along a layer 112 contributes toa compact and simplified structure of the electronic device 100 in thatsuch configuration avoids the need for additional cables or attachmentfeatures to communicate the antenna 106 with the circuit components 104.In some embodiments, the electronic device 100 may include additionaltrace pathways to serialize the circuit components 104 and render theelectronic device 100 viewable with standard imaging equipment (e.g.,X-ray equipment).

The electrodes 108 are embodied as generally cylindrical structures thatcan be secured to the pads 110 at the contact sites 114. The electrodes108 typically have a length of about 0.5 mm to about 6 mm and aninternal diameter of about 0.9 mm to about 1.5 mm.

Referring to FIG. 4, the electrodes 108 are attached to the contactsites 114 and around the circuit board 102 at joints 118 that extendalong axes 120 of the electrodes 108. The joints 118 provide additionalsurface area at which the electrodes 108 can be attached to the circuitboard 102. The electrodes 108 and the joints 118 are typically made ofone or more materials, such as stainless steel, platinum,platinum-iridium, gallium-nitride, titanium-nitride, iridium-oxide, orother materials. The joints 118 have a circular cross-sectional shapethat provides an outer surface at which the electrodes 108 can besufficiently attached in extent. In some embodiments, the joints 118 areattached to the circuit board 102 at the contact sites 114 in anautomatic manner via surface mount techniques that utilize tape and reelmachine mechanisms or soldered by hand. The joints 118 typically have athickness of about 0.05 mm to about 0.5 mm and typically have a lengththat is a bit shorter than the respective electrodes 108.

Referring to FIG. 5, the electrodes 108 may then be attached to thecircuit board at the joints 118 using various attachment techniques,such as laser welding, soldering, and conductive epoxy application(e.g., chemical bonding). Such techniques can be carried outautomatically using computer controlled processing heads (e.g., laserheads 122, soldering tips 124, and syringes 126 applying epoxy 140) thatcan be controlled to attach multiple electrodes 108 to the joints 118 onthe circuit board 102 in one pass or in multiple passes. In this manner,the electrodes 108 can be attached to the circuit board 102 in a uniformmanner within specified tolerances and without cables (e.g., stainlesssteel wires, braided wires, or other wires) extending along the circuitboard 102 and between the electrodes 108 that would otherwise need to bemanually assembled with the electrodes 108 and the circuit board 102. Ascompared to conventional implantable electronic devices for whichelectrodes are secured to a circuit board via multiple cables, theelectronic device 100 is more easily assembled (e.g., automatically andmore quickly at a lower cost), more flexible, can withstand more bendingforces (e.g., avoiding the problem of cables popping off of electrodes),is more mechanically robust within a moving body, and is therefore lesslikely to fail mechanically. Additionally, the electrodes 108 areassembled more uniformly with respect to positional accuracy andmechanical integrity, as compared to electrodes that are manuallysecured to a circuit board with multiple cables.

In some embodiments, an overall footprint and three-dimensional shape ofthe electronic device 100 are selected to provide optimized electricaland mechanical performance of the circuit components 104 and theelectrodes 108, provide minimal tissue contacting surface areas, andprovide an anchoring structure that prevents or reduces movement of theelectronic device 100 within the body. In some embodiments,

While the electronic device 100 has been described and illustrated asincluding certain dimensions, sizes, shapes, materials, arrangements,and configurations, in some embodiments, electronic devices that aresimilar in structure and function to the electronic device 100 mayinclude different dimensions, sizes, shapes, materials, arrangements, orconfigurations. For example, FIG. 6 illustrates an electronic device1500 that is similar in structure and function to the electronic device100, except that the circuit board 102 is attached to the electrodes 108along outside surfaces of the electrodes 108. In some embodiments,separate connection to the electrodes 108 can advantageously offer awider variety of options for the form factor of the electrodes 108 oradvantageously allow interfacing with previously placed electrodes thathave a connector end that can be mated to a header connector. Aconnector header can allow for the electrode connectors to mate to thecircuitry elements as a separate piece.

While the electronic devices 100, 1500 have been described andillustrated as including cylindrical electrodes 118 and circular joints118, in some embodiments, electronic devices that are similar instructure and function to either of the electronic devices 100, 1500 mayinclude electrodes and joints that have different shapes or surfaceprofiles. For example, as illustrated in FIG. 7, electronic devices 300a, 300 b, 300 c include joints 318 a, 318 b, 318 c with non-circular(e.g., generally rectangular or trapezoidal) cross-sectional shapes.While the electronic device 300 a includes the electrodes 108 that areformed to be adequately attached to the joint 318 a, the electronicdevices 300 b, 300 c include electrodes 306 b, 306 c that havenon-circular interior cross-sectional shapes with thickened wallsections 330 b, 330 c that are formed to complement the joints 318 b,318 c. In particular, the wall section 330 b provides a flat interiorsurface for mating with the thin, rectangular joint 318 b, and the wallsection 330 c provides a recessed cutout for mating with the trapezoidaljoint 318 c. As shown in FIG. 7, the electrodes 306 b, 306 c can also beattached to the circuit board 102 via various attachment techniques,such as laser welding, soldering, and conductive epoxy application, asdiscussed above with respect to the electronic device 100.

FIG. 8 illustrates electronic devices 400 a, 400 b, 400 c, 400 d forwhich electrodes are secured to the circuit board 102 along one side ofthe circuit board 102 such that the circuit board 102 is positionedexternal to the electrodes. The electronic devices 400 a, 400 b, 400 c,400 d include joints 418 a, 418 b, 418 c, 418 d with non-circular (e.g.,generally rectangular, trapezoidal, and other) cross-sectional shapes.While the electronic devices 400 a, 400 d include the electrodes 108that are formed to be adequately attached to the joint 418 a, 418 d, theelectronic devices 400 b, 400 c include electrodes 406 b, 406 c withnon-circular exterior cross-sectional shapes with thickened wallsections 430 b, 430 c that are formed to complement the joints 418 b,418 c. In particular, the wall section 430 b provides a flat interiorsurface for mating with the rectangular joint 418 b, and the wallsection 430 c provides a recessed cutout for mating with the trapezoidaljoint 418 c. As shown in FIG. 8, the electrodes 406 b, 406 c can also beattached to the circuit board 102 via various attachment techniques,such as laser welding, soldering, and conductive epoxy application, asdiscussed above with respect to the electronic devices 100, 1500.

While the electronic devices 100, 300, 400, 1500 have been described andillustrated with electrode attachment to a circuit board using laserwelding, soldering, or conductive epoxy application, in someembodiments, electronic devices that are substantially similar inconstruction and function to the any of electronic devices 100, 300,400, 1500 may include electrodes that are attached via other techniques,such as welding, brazing, crimping, press fitting, swaging, ormechanical locking. For example, FIGS. 9 and 10 illustrate electronicdevices 500, 600 for which the electrodes 108 are secured to the circuitboard 102 within snap rings 532, 632 that are themselves attached to thecircuit board 102 using standard surface mount pick and place with areel of components, or soldered by hand.

While the electronic devices 100, 300, 400, 500, 600, 1500 have beendescribed and illustrated with electrode attachment to a circuit boardvia the joints 118, 318, 418 and snap rings 532, 632, in someembodiments, electronic devices that are otherwise similar inconstruction and function to the any of electronic devices 100, 300,400, 500, 600, 1500 may include electrodes that are attached directly toa circuit board using any of the above-mentioned techniques without suchjoints. In some embodiments, a joint may be integrated directly withinsuch electrodes.

While the electronic device 100 has been illustrated with a single rowof circuit components 104 and electrodes 108, in some embodiments,electronic devices that are similar in construction and function to theelectronic device 100 may include more than one row of circuitcomponents 104 and electrodes 108 or a different arrangement of circuitcomponents 104 and electrodes 108. For example, FIGS. 11-16 illustrateelectronic devices 700, 800 that have different arrangements of circuitcomponents 104 and electrodes 108. The electronic devices 700, 800 areotherwise similar in structure and function to the electronic device 100and accordingly further include circuit boards 702, 802, layers 712,812, contact sites 714, 814, antennas 706, 806, and the pads 110. In theexample electronic device 800, the wider circuit board 102 allows for alarger antenna structure.

FIG. 17 illustrates an electronic device 900 that is substantiallysimilar in structure and function to the electronic device 800, exceptthat the electronic device 900 includes an antenna 906 along a top layer912 of a circuit board 902. For such configuration in which the antenna906 is oriented parallel to the circuit components 104, the circuitcomponents 104 compete with the antenna 906 for an incident polarizedtransmission signal 940.

In some embodiments, an electronic device that is otherwise similar inconstruction and function to the electronic device 900 may include anantenna that is oriented perpendicular to circuit components 104. Forexample, FIG. 18 illustrates an electronic device 1000 that includessuch an antenna 1006 disposed atop a circuit board 1002. Accordingly,the circuit components 104 do not compete with the antenna 1006 for anincident polarized transmission signal 1040, which is orientedperpendicular to the circuit components 104. In some embodiments, theantenna 1006 may be coiled upon itself to reduce a footprint of theelectronic device 1000, as illustrated in FIG. 19. Such configurationsmay be introduced into the body in ways other than through an introducerneedle.

In some embodiments, an electronic device that is otherwise similar inconstruction and function to any of the above-discussed electronicdevices may include electrodes that are positioned on both ends of acircuit board. For example, FIG. 20 illustrates a circuit board 1102 ofa circuit board 1100 that includes contact sites 1114 for electrodes onboth ends of the circuit board 1102. Though other components have beenomitted for illustration, the electronic device 1100 may otherwise besimilar in construction and function to the electronic device 100.

In some embodiments, an electronic device that is otherwise similar inconstruction and function to any of the above-discussed electronicdevices may include an antenna that is made up of multiple portions. Forexample, FIGS. 21 and 22 illustrate electronic devices 1200, 1300 thatinclude antennas 1206, 1306 that are formed of two portions along toplayers of circuit boards 102, 802. Though other components have beenomitted for illustration, the electronic devices 1200, 1300 mayotherwise be similar in construction and function to the electronicdevices 100, 800.

In some embodiments, an electronic device that is otherwise similar inconstruction and function to any of the above-discussed electronicdevices may not include an embedded antenna.

In some embodiments, an electronic device that is otherwise similar inconstruction and function to any of the above-discussed electronicdevices may include exposed and plated traces instead of electrodes.

In some embodiments, any of the above-discussed electronic devices maybe provided as part of a tissue stimulation system, such as a neuralstimulation system 1400, shown in FIG. 23. The neural stimulation system1400 may be used to send electrical stimulation to targeted nerve tissueby using remote radio frequency (RF) energy without cables and withoutinductive coupling to power the electronic device 100, provided as apassive stimulator. In some examples, the targeted nerve tissues may bein the spinal column and include the spinothalamic tracts, dorsal horn,dorsal root ganglia, dorsal roots, dorsal column fibers, and peripheralnerves bundles leaving the dorsal column or brainstem, as well as anycranial nerves, abdominal, thoracic, or trigeminal ganglia nerves, nervebundles of the cerebral cortex, deep brain and any sensory or motornerves.

The neural stimulation system 1400 may include a controller module(e.g., an RF pulse generator module) and the passive electronic device100, which includes one or more dipole antennas 106, circuit components104, and electrodes 108 that can contact targeted neural tissue toprovide tissue stimulation. The RF pulse generator module may include anantenna and may be configured to transfer energy from the module antennato the implanted antennas. The circuit components 104 may be configuredto generate electrical pulses suitable for neural stimulation using thetransferred energy and to supply the electrical pulses to the electrodes108 so that the pulses are applied to the neural tissue. For instance,the circuit components 104 may include wave conditioning circuitry thatrectifies the received RF signal (for example, using a diode rectifier),transforms the RF energy to a low frequency signal suitable for thestimulation of neural tissue, and presents the resulting waveform to anelectrode array. The circuit components 104 may also include circuitryfor communicating information back to the RF pulse generator module tofacilitate a feedback control mechanism for stimulation parametercontrol. For example, the electronic device 100 may send to the RF pulsegenerator module a stimulus feedback signal that is indicative ofparameters of the electrical pulses, and the RF pulse generator modulemay employ the stimulus feedback signal to adjust parameters of thesignal sent to the neural stimulator.

Still referring to FIG. 23, neural stimulation system 1400 includes aprogrammer module 1402, an RF pulse generator module 1406, a transmit(TX) antenna 1410 (e.g., a patch antenna, slot antenna, or a dipoleantenna), and the electronic device 100. The programmer module 102 maybe a computer device, such as a smart phone, running a softwareapplication that supports a wireless connection 1404, such asBluetooth.RTM. The application can enable the user to view the systemstatus and diagnostics, change various parameters, increase/decrease thedesired stimulus amplitude of the electrode pulses, and adjust feedbacksensitivity of the RF pulse generator module 1406, among otherfunctions.

The RF pulse generator module 1406 may include communication electronicsthat support the wireless connection 1404, the stimulation circuitry,and the battery to power the generator electronics. In someimplementations, the RF pulse generator module 1406 includes the TXantenna embedded into its packaging form factor while, in otherimplementations, the TX antenna is connected to the RF pulse generatormodule 1406 through a wired connection 1408 or a wireless connection(not shown). The TX antenna 1410 may be coupled directly to tissue tocreate an electric field that powers the electronic device 100. The TXantenna 1410 communicates with the implanted electronic device 100through an RF interface. For instance, the TX antenna 1410 radiates anRF transmission signal that is modulated and encoded by the RF pulsegenerator module 1410. The electronic device 100 contains one or moreantennas 106, such as dipole antenna(s), to receive and transmit throughRF interface 1412. In particular, the coupling mechanism between antenna1410 and the one or more antennas 106 on the electronic device 100 iselectrical radiative coupling and not inductive coupling. In otherwords, the coupling is through an electric field rather than a magneticfield.

Through this electrical radiative coupling, the TX antenna 1410 canprovide an input signal to the implanted electronic device 100. Thisinput signal contains energy and may contain information encodingstimulus waveforms to be applied at the electrodes 108 of the electronicdevice 100. In some implementations, the power level of this inputsignal directly determines an applied amplitude (for example, power,current, or voltage) of the one or more electrical pulses created usingthe electrical energy contained in the input signal. Within theimplanted electronic device 100 are the circuit components 106 fordemodulating the RF transmission signal, and the electrodes 108 todeliver the stimulation to surrounding neuronal tissue.

The RF pulse generator module 1406 can be implanted subcutaneously, orit can be worn external to the body. When external to the body, the RFgenerator module 1406 can be incorporated into a belt or harness designto allow for electric radiative coupling through the skin and underlyingtissue to transfer power and/or control parameters to the electronicdevice 100. In either event, receiver circuit components 104 internal tothe electronic device 100 can capture the energy radiated by the TXantenna 1410 and convert this energy to an electrical waveform. Thereceiver circuit components 404 may further modify the waveform tocreate an electrical pulse suitable for the stimulation of neuraltissue, and this pulse may be delivered to the tissue via the electrodes108.

In some implementations, the RF pulse generator module 1406 can remotelycontrol the stimulus parameters (that is, the parameters of theelectrical pulses applied to the neural tissue) and monitor feedbackfrom the wireless electronic device 100 based on RF signals receivedfrom the electronic device 100. A feedback detection algorithmimplemented by the RF pulse generator module 1406 can monitor data sentwirelessly from the implanted electronic device 100, includinginformation about the energy that the electronic device 100 is receivingfrom the RF pulse generator 1406 and information about the stimuluswaveform being delivered to the electrodes 108. In order to provide aneffective therapy for a given medical condition, the system can be tunedto provide the optimal amount of excitation or inhibition to the nervefibers by electrical stimulation. A closed loop feedback control methodcan be used in which the output signals from the implanted electronicdevice 100 are monitored and used to determine the appropriate level ofneural stimulation current for maintaining effective neuronalactivation, or, in some cases, the patient can manually adjust theoutput signals in an open loop control method.

FIG. 24 depicts a detailed diagram of the neural stimulation system1400. As depicted, the programming module 1402 may comprise user inputsystem 202 and communication subsystem 208. The user input system 221may allow various parameter settings to be adjusted (in some cases, inan open loop fashion) by the user in the form of instruction sets. Thecommunication subsystem 208 may transmit these instruction sets (andother information) via the wireless connection 1404, such as Bluetoothor Wi-Fi, to the RF pulse generator module 1406, as well as receive datafrom module 1406.

For instance, the programmer module 102, which can be utilized formultiple users, such as a patient's control unit or clinician'sprogrammer unit, can be used to send stimulation parameters to the RFpulse generator module 1406. The stimulation parameters that can becontrolled may include pulse amplitude, pulse frequency, and pulse widthin the ranges of 0 to 20 mA, 0 to 2000 Hz Pulse Width, and 0 to 2 ms,respectively. In this context the term pulse refers to the phase of thewaveform that directly produces stimulation of the tissue; theparameters of the charge-balancing phase (described below) can similarlybe controlled. The patient and/or the clinician can also optionallycontrol overall duration and pattern of treatment.

The electronic device 100 or RF pulse generator module 1406 may beinitially programmed to meet the specific parameter settings for eachindividual patient during the initial implantation procedure. Becausemedical conditions or the body itself can change over time, the abilityto re-adjust the parameter settings may be beneficial to ensure ongoingefficacy of the neural modulation therapy.

The programmer module 1402 may be functionally a smart device andassociated application. The smart device hardware may include a CPU 206and be used as a vehicle to handle touchscreen input on a graphical userinterface (GUI) 204, for processing and storing data.

The RF pulse generator module 1406 may be connected via wired connection1408 to an external TX antenna 1410. Alternatively, both the antenna andthe RF pulse generator are located subcutaneously (not shown).

The signals sent by RF pulse generator module 1406 to the implantedstimulator 1414 may include both power and parameter-setting attributesin regards to stimulus waveform, amplitude, pulse width, and frequency.The RF pulse generator module 1406 can also function as a wirelessreceiving unit that receives feedback signals from the electronic device100. To that end, the RF pulse generator module 1406 may containmicroelectronics or other circuitry to handle the generation of thesignals transmitted to the electronic device 100 as well as handlefeedback signals, such as those from electronic device 100. For example,the RF pulse generator module 1406 may comprise controller subsystem214, high-frequency oscillator 218, RF amplifier 216, a RF switch, and afeedback subsystem 212.

The controller subsystem 214 may include a CPU 230 to handle dataprocessing, a memory subsystem 228 such as a local memory, communicationsubsystem 234 to communicate with programmer module 102 (includingreceiving stimulation parameters from programmer module), pulsegenerator circuitry 236, and digital/analog (D/A) converters 232.

The controller subsystem 214 may be used by the patient and/or theclinician to control the stimulation parameter settings (for example, bycontrolling the parameters of the signal sent from RF pulse generatormodule 1406 to electronic device 100). These parameter settings canaffect, for example, the power, current level, or shape of the one ormore electrical pulses. The programming of the stimulation parameterscan be performed using the programming module 1402, as described above,to set the repetition rate, pulse width, amplitude, and waveform thatwill be transmitted by RF energy to the receive (RX) antenna 238 (e.g.,an embodiment of the antenna 106), typically a dipole antenna (althoughother types may be used), in the wireless implanted electronic device100. The clinician may have the option of locking and/or hiding certainsettings within the programmer interface, thus limiting the patient'sability to view or adjust certain parameters because adjustment ofcertain parameters may require detailed medical knowledge ofneurophysiology, neuroanatomy, protocols for neural modulation, andsafety limits of electrical stimulation. The controller subsystem 214may store received parameter settings in the local memory subsystem 228,until the parameter settings are modified by new input data receivedfrom the programming module 1402. The CPU 206 may use the parametersstored in the local memory to control the pulse generator circuitry 236to generate a stimulus waveform that is modulated by a high frequencyoscillator 218 in the range from 300 MHz to 8 GHz. The resulting RFsignal may then be amplified by RF amplifier 226 and then sent throughan RF switch 223 to the TX antenna 1410 to reach through depths oftissue to the RX antenna 238.

In some implementations, the RF signal sent by TX antenna 1410 maysimply be a power transmission signal used by electronic device 100 togenerate electric pulses. In other implementations, a telemetry signalmay also be transmitted to the electronic device 100 to sendinstructions about the various operations of the electronic device 100.The telemetry signal may be sent by the modulation of the carrier signal(through the skin if external, or through other body tissues if thepulse generator module 1406 is implanted subcutaneously). The telemetrysignal is used to modulate the carrier signal (a high frequency signal)that is coupled onto the implanted antenna(s) 238 and does not interferewith the input received on the same lead to power the implant. In oneembodiment the telemetry signal and powering signal are combined intoone signal, where the RF telemetry signal is used to modulate the RFpowering signal, and thus the implanted stimulator is powered directlyby the received telemetry signal; separate subsystems in the stimulatorharness the power contained in the signal and interpret the data contentof the signal.

The RF switch 223 may be a multipurpose device such as a dualdirectional coupler, which passes the relatively high amplitude,extremely short duration RF pulse to the TX antenna 1410 with minimalinsertion loss while simultaneously providing two low-level outputs tofeedback subsystem 212; one output delivers a forward power signal tothe feedback subsystem 212, where the forward power signal is anattenuated version of the RF pulse sent to the TX antenna 1410, and theother output delivers a reverse power signal to a different port of thefeedback subsystem 212, where reverse power is an attenuated version ofthe reflected RF energy from the TX Antenna 1410.

During the on-cycle time (when an RF signal is being transmitted toelectronic device 100), the RF switch 223 is set to send the forwardpower signal to feedback subsystem. During the off-cycle time (when anRF signal is not being transmitted to the electronic device 100), the RFswitch 223 can change to a receiving mode in which the reflected RFenergy and/or RF signals from the electronic device 100 are received tobe analyzed in the feedback subsystem 212.

The feedback subsystem 212 of the RF pulse generator module 1406 mayinclude reception circuitry to receive and extract telemetry or otherfeedback signals from electronic device 100 and/or reflected RF energyfrom the signal sent by TX antenna 1410. The feedback subsystem mayinclude an amplifier 226, a filter 224, a demodulator 222, and an A/Dconverter 220.

The feedback subsystem 212 receives the forward power signal andconverts this high-frequency AC signal to a DC level that can be sampledand sent to the controller subsystem 214. In this way thecharacteristics of the generated RF pulse can be compared to a referencesignal within the controller subsystem 214. If a disparity (error)exists in any parameter, the controller subsystem 214 can adjust theoutput to the RF pulse generator 1406. The nature of the adjustment canbe, for example, proportional to the computed error. The controllersubsystem 214 can incorporate additional inputs and limits on itsadjustment scheme such as the signal amplitude of the reverse power andany predetermined maximum or minimum values for various pulseparameters.

The reverse power signal can be used to detect fault conditions in theRF-power delivery system. In an ideal condition, when TX antenna 1410has perfectly matched impedance to the tissue that it contacts, theelectromagnetic waves generated from the RF pulse generator 1406 passunimpeded from the TX antenna 1410 into the body tissue. However, inreal-world applications a large degree of variability may exist in thebody types of users, types of clothing worn, and positioning of theantenna 1410 relative to the body surface. Since the impedance of theantenna 1410 depends on the relative permittivity of the underlyingtissue and any intervening materials, and also depends on the overallseparation distance of the antenna from the skin, in any givenapplication there can be an impedance mismatch at the interface of theTX antenna 1410 with the body surface. When such a mismatch occurs, theelectromagnetic waves sent from the RF pulse generator 1406 arepartially reflected at this interface, and this reflected energypropagates backward through the antenna feed.

The dual directional coupler RF switch 223 may prevent the reflected RFenergy propagating back into the amplifier 226, and may attenuate thisreflected RF signal and send the attenuated signal as the reverse powersignal to the feedback subsystem 212. The feedback subsystem 212 canconvert this high-frequency AC signal to a DC level that can be sampledand sent to the controller subsystem 214. The controller subsystem 214can then calculate the ratio of the amplitude of the reverse powersignal to the amplitude of the forward power signal. The ratio of theamplitude of reverse power signal to the amplitude level of forwardpower may indicate severity of the impedance mismatch.

In order to sense impedance mismatch conditions, the controllersubsystem 214 can measure the reflected-power ratio in real time, andaccording to preset thresholds for this measurement, the controllersubsystem 214 can modify the level of RF power generated by the RF pulsegenerator 1406. For example, for a moderate degree of reflected powerthe course of action can be for the controller subsystem 214 to increasethe amplitude of RF power sent to the TX antenna 1410, as would beneeded to compensate for slightly non-optimum but acceptable TX antennacoupling to the body. For higher ratios of reflected power, the courseof action can be to prevent operation of the RF pulse generator 1406 andset a fault code to indicate that the TX antenna 1410 has little or nocoupling with the body. This type of reflected-power fault condition canalso be generated by a poor or broken connection to the TX antenna. Ineither case, it may be desirable to stop RF transmission when thereflected-power ratio is above a defined threshold, because internallyreflected power can lead to unwanted heating of internal components, andthis fault condition means the system cannot deliver sufficient power tothe implanted wireless neural stimulator and thus cannot deliver therapyto the user.

The controller 242 of the electronic device 100 may transmitinformational signals, such as a telemetry signal, through the antenna238 to communicate with the RF pulse generator module 1406 during itsreceive cycle. For example, the telemetry signal from the electronicdevice 100 may be coupled to the modulated signal on the dipoleantenna(s) 238, during the on and off state of the transistor circuit toenable or disable a waveform that produces the corresponding RF burstsnecessary to transmit to the external (or remotely implanted) pulsegenerator module 1406. The antenna(s) 238 may be connected to electrodes254 (e.g., embodiments of the electrodes 108) in contact with tissue toprovide a return path for the transmitted signal. An A/D (not shown)converter can be used to transfer stored data to a serialized patternthat can be transmitted on the pulse modulated signal from the internalantenna(s) 238 of the neural stimulator.

A telemetry signal from the implanted wireless electronic device 100 mayinclude stimulus parameters such as the power or the amplitude of thecurrent that is delivered to the tissue from the electrodes. Thefeedback signal can be transmitted to the RF pulse generator module 1406to indicate the strength of the stimulus at the nerve bundle by means ofcoupling the signal to the implanted RX antenna 238, which radiates thetelemetry signal to the external (or remotely implanted) RF pulsegenerator module 1406. The feedback signal can include either or both ananalog and digital telemetry pulse modulated carrier signal. Data suchas stimulation pulse parameters and measured characteristics ofstimulator performance can be stored in an internal memory device withinthe implanted electronic device 100, and sent on the telemetry signal.The frequency of the carrier signal may be in the range of at 300 MHz to8 GHz.

In the feedback subsystem 212, the telemetry signal can be downmodulated using demodulator 222 and digitized by being processed throughan analog to digital (A/D) converter 220. The digital telemetry signalmay then be routed to a CPU 230 with embedded code, with the option toreprogram, to translate the signal into a corresponding currentmeasurement in the tissue based on the amplitude of the received signal.The CPU 230 of the controller subsystem 214 can compare the reportedstimulus parameters to those held in local memory 228 to verify that theelectronic device 100 delivered the specified stimuli to tissue. Forexample, if the electronic device 100 reports a lower current than wasspecified, the power level from the RF pulse generator module 1406 canbe increased so that the implanted electronic device 100 will have moreavailable power for stimulation. The implanted electronic device 100 cangenerate telemetry data in real time, for example, at a rate of 8 kbitsper second. All feedback data received from the implanted electronicdevice 100 can be logged against time and sampled to be stored forretrieval to a remote monitoring system accessible by the health careprofessional for trending and statistical correlations.

The sequence of remotely programmable RF signals received by theinternal antenna(s) 238 may be conditioned into waveforms that arecontrolled within the electronic device 100 by the control subsystem 242and routed to the appropriate electrodes 254 that are placed inproximity to the tissue to be stimulated. For instance, the RF signaltransmitted from the RF pulse generator module 1406 may be received byRX antenna 238 and processed by circuitry, such as waveform conditioningcircuitry 240, within the implanted wireless electronic device 100 to beconverted into electrical pulses applied to the electrodes 254 throughelectrode interface 252. In some implementations, the implantedelectronic device 100 contains between two to sixteen electrodes 254.

The waveform conditioning circuitry 240 may include a rectifier 244,which rectifies the signal received by the RX antenna 238. The rectifiedsignal may be fed to the controller 242 for receiving encodedinstructions from the RF pulse generator module 1406. The rectifiersignal may also be fed to a charge balance component 246 that isconfigured to create one or more electrical pulses based such that theone or more electrical pulses result in a substantially zero net chargeat the one or more electrodes (that is, the pulses are charge balanced).The charge balanced pulses are passed through the current limiter 248 tothe electrode interface 252, which applies the pulses to the electrodes254 as appropriate.

The current limiter 248 insures the current level of the pulses appliedto the electrodes 254 is not above a threshold current level. In someimplementations, an amplitude (for example, current level, voltagelevel, or power level) of the received RF pulse directly determines theamplitude of the stimulus. In this case, it may be particularlybeneficial to include current limiter 248 to prevent excessive currentor charge being delivered through the electrodes, although currentlimiter 248 may be used in other implementations where this is not thecase. Generally, for a given electrode having several square millimeterssurface area, it is the charge per phase that should be limited forsafety (where the charge delivered by a stimulus phase is the integralof the current). But, in some cases, the limit can instead be placed onthe current, where the maximum current multiplied by the maximumpossible pulse duration is less than or equal to the maximum safecharge. More generally, the limiter 248 acts as a charge limiter thatlimits a characteristic (for example, current or duration) of theelectrical pulses so that the charge per phase remains below a thresholdlevel (typically, a safe-charge limit).

In the event the implanted wireless electronic device 100 receives a“strong” pulse of RF power sufficient to generate a stimulus that wouldexceed the predetermined safe-charge limit, the current limiter 248 canautomatically limit or “clip” the stimulus phase to maintain the totalcharge of the phase within the safety limit. The current limiter 248 maybe a passive current limiting component that cuts the signal to theelectrodes 254 once the safe current limit (the threshold current level)is reached. Alternatively, or additionally, the current limiter 248 maycommunicate with the electrode interface 252 to turn off all electrodes254 to prevent tissue damaging current levels.

A clipping event may trigger a current limiter feedback control mode.The action of clipping may cause the controller to send a thresholdpower data signal to the pulse generator 238. The feedback subsystem 212detects the threshold power signal and demodulates the signal into datathat is communicated to the controller subsystem 214. The controllersubsystem 214 algorithms may act on this current-limiting condition byspecifically reducing the RF power generated by the RF pulse generator,or cutting the power completely. In this way, the pulse generator 1406can reduce the RF power delivered to the body if the implanted wirelesselectronic device 100 reports it is receiving excess RF power.

The controller 250 of the stimulator 205 may communicate with theelectrode interface 252 to control various aspects of the electrodesetup and pulses applied to the electrodes 254. The electrode interface252 may act as a multiplex and control the polarity and switching ofeach of the electrodes 254. For instance, in some implementations, thewireless stimulator 1406 has multiple electrodes 254 in contact withtissue, and for a given stimulus the RF pulse generator module 1406 canarbitrarily assign one or more electrodes to 1) act as a stimulatingelectrode, 2) act as a return electrode, or 3) be inactive bycommunication of assignment sent wirelessly with the parameterinstructions, which the controller 250 uses to set electrode interface252 as appropriate. It may be physiologically advantageous to assign,for example, one or two electrodes as stimulating electrodes and toassign all remaining electrodes as return electrodes.

Also, in some implementations, for a given stimulus pulse, thecontroller 250 may control the electrode interface 252 to divide thecurrent arbitrarily (or according to instructions from pulse generatormodule 1406) among the designated stimulating electrodes. This controlover electrode assignment and current control can be advantageousbecause in practice the electrodes 254 may be spatially distributedalong various neural structures, and through strategic selection of thestimulating electrode location and the proportion of current specifiedfor each location, the aggregate current distribution in tissue can bemodified to selectively activate specific neural targets. This strategyof current steering can improve the therapeutic effect for the patient.

In another implementation, the time course of stimuli may be arbitrarilymanipulated. A given stimulus waveform may be initiated at a timeT_start and terminated at a time T final, and this time course may besynchronized across all stimulating and return electrodes; further, thefrequency of repetition of this stimulus cycle may be synchronous forall the electrodes. However, controller 250, on its own or in responseto instructions from pulse generator 238, can control electrodeinterface 252 to designate one or more subsets of electrodes to deliverstimulus waveforms with non-synchronous start and stop times, and thefrequency of repetition of each stimulus cycle can be arbitrarily andindependently specified.

For example, a stimulator having eight electrodes may be configured tohave a subset of five electrodes, called set A, and a subset of threeelectrodes, called set B. Set A might be configured to use two of itselectrodes as stimulating electrodes, with the remainder being returnelectrodes. Set B might be configured to have just one stimulatingelectrode. The controller 250 could then specify that set A deliver astimulus phase with 3 mA current for a duration of 200 us followed by a400 us charge-balancing phase. This stimulus cycle could be specified torepeat at a rate of 60 cycles per second. Then, for set B, thecontroller 250 could specify a stimulus phase with 1 mA current forduration of 500 us followed by a 800 us charge-balancing phase. Therepetition rate for the set-B stimulus cycle can be set independently ofset A, say for example it could be specified at 25 cycles per second.Or, if the controller 250 was configured to match the repetition ratefor set B to that of set A, for such a case the controller 250 canspecify the relative start times of the stimulus cycles to be coincidentin time or to be arbitrarily offset from one another by some delayinterval.

In some implementations, the controller 250 can arbitrarily shape thestimulus waveform amplitude, and may do so in response to instructionsfrom pulse generator 1406. The stimulus phase may be delivered by aconstant-current source or a constant-voltage source, and this type ofcontrol may generate characteristic waveforms that are static, e.g. aconstant-current source generates a characteristic rectangular pulse inwhich the current waveform has a very steep rise, a constant amplitudefor the duration of the stimulus, and then a very steep return tobaseline. Alternatively, or additionally, the controller 250 canincrease or decrease the level of current at any time during thestimulus phase and/or during the charge-balancing phase. Thus, in someimplementations, the controller 250 can deliver arbitrarily shapedstimulus waveforms such as a triangular pulse, sinusoidal pulse, orGaussian pulse for example. Similarly, the charge-balancing phase can bearbitrarily amplitude-shaped, and similarly a leading anodic pulse(prior to the stimulus phase) may also be amplitude-shaped.

As described above, the electronic device 100 may include a chargebalancing component 246. Generally, for constant current stimulationpulses, pulses should be charge balanced by having the amount ofcathodic current should equal the amount of anodic current, which istypically called biphasic stimulation. Charge density is the amount ofcurrent times the duration it is applied, and is typically expressed inthe units uC/cm². In order to avoid the irreversible electrochemicalreactions such as pH change, electrode dissolution as well as tissuedestruction, no net charge should appear at the electrode-electrolyteinterface, and it is generally acceptable to have a charge density lessthan 30 uC/cm². Biphasic stimulating current pulses ensure that no netcharge appears at the electrode after each stimulation cycle and theelectrochemical processes are balanced to prevent net dc currents. Theelectronic device 100 may be designed to ensure that the resultingstimulus waveform has a net zero charge. Charge balanced stimuli arethought to have minimal damaging effects on tissue by reducing oreliminating electrochemical reaction products created at theelectrode-tissue interface.

A stimulus pulse may have a negative-voltage or current, called thecathodic phase of the waveform. Stimulating electrodes may have bothcathodic and anodic phases at different times during the stimulus cycle.An electrode that delivers a negative current with sufficient amplitudeto stimulate adjacent neural tissue is called a “stimulating electrode.”During the stimulus phase the stimulating electrode acts as a currentsink. One or more additional electrodes act as a current source andthese electrodes are called “return electrodes.” Return electrodes areplaced elsewhere in the tissue at some distance from the stimulatingelectrodes. When a typical negative stimulus phase is delivered totissue at the stimulating electrode, the return electrode has a positivestimulus phase. During the subsequent charge-balancing phase, thepolarities of each electrode are reversed.

In some implementations, the charge balance component 246 uses ablocking capacitor(s) placed electrically in series with the stimulatingelectrodes and body tissue, between the point of stimulus generationwithin the stimulator circuitry and the point of stimulus delivery totissue. In this manner, a resistor-capacitor (RC) network may be formed.In a multi-electrode stimulator, one charge-balance capacitor(s) may beused for each electrode or a centralized capacitor(s) may be used withinthe stimulator circuitry prior to the point of electrode selection. TheRC network can block direct current (DC), however it can also preventlow-frequency alternating current (AC) from passing to the tissue. Thefrequency below which the series RC network essentially blocks signalsis commonly referred to as the cutoff frequency, and in one embodimentthe design of the stimulator system may ensure the cutoff frequency isnot above the fundamental frequency of the stimulus waveform. In thisembodiment of the present invention, the wireless stimulator may have acharge-balance capacitor with a value chosen according to the measuredseries resistance of the electrodes and the tissue environment in whichthe stimulator is implanted. By selecting a specific capacitance valuethe cutoff frequency of the RC network in this embodiment is at or belowthe fundamental frequency of the stimulus pulse.

In other implementations, the cutoff frequency may be chosen to be at orabove the fundamental frequency of the stimulus, and in this scenariothe stimulus waveform created prior to the charge-balance capacitor,called the drive waveform, may be designed to be non-stationary, wherethe envelope of the drive waveform is varied during the duration of thedrive pulse. For example, in one embodiment, the initial amplitude ofthe drive waveform is set at an initial amplitude Vi, and the amplitudeis increased during the duration of the pulse until it reaches a finalvalue k*Vi. By changing the amplitude of the drive waveform over time,the shape of the stimulus waveform passed through the charge-balancecapacitor is also modified. The shape of the stimulus waveform may bemodified in this fashion to create a physiologically advantageousstimulus.

In some implementations, the wireless electronic device 100 may create adrive-waveform envelope that follows the envelope of the RF pulsereceived by the receiving dipole antenna(s) 238. In this case, the RFpulse generator module 1406 can directly control the envelope of thedrive waveform within the wireless electronic device 100, and thus noenergy storage may be required inside the stimulator itself. In thisimplementation, the stimulator circuitry may modify the envelope of thedrive waveform or may pass it directly to the charge-balance capacitorand/or electrode-selection stage.

In some implementations, the implanted electronic device 100 may delivera single-phase drive waveform to the charge balance capacitor or it maydeliver multiphase drive waveforms. In the case of a single-phase drivewaveform, for example, a negative-going rectangular pulse, this pulsecomprises the physiological stimulus phase, and the charge-balancecapacitor is polarized (charged) during this phase. After the drivepulse is completed, the charge balancing function is performed solely bythe passive discharge of the charge-balance capacitor, where isdissipates its charge through the tissue in an opposite polarityrelative to the preceding stimulus. In one implementation, a resistorwithin the stimulator facilitates the discharge of the charge-balancecapacitor. In some implementations, using a passive discharge phase, thecapacitor may allow virtually complete discharge prior to the onset ofthe subsequent stimulus pulse. In the case of multiphase drive waveformsthe electronic device 100 may perform internal switching to passnegative-going or positive-going pulses (phases) to the charge-balancecapacitor. These pulses may be delivered in any sequence and withvarying amplitudes and waveform shapes to achieve a desiredphysiological effect. For example, the stimulus phase may be followed byan actively driven charge-balancing phase, and/or the stimulus phase maybe preceded by an opposite phase. Preceding the stimulus with anopposite-polarity phase, for example, can have the advantage of reducingthe amplitude of the stimulus phase required to excite tissue.

In some implementations, the amplitude and timing of stimulus andcharge-balancing phases is controlled by the amplitude and timing of RFpulses from the RF pulse generator module 1406, and in others thiscontrol may be administered internally by circuitry onboard theelectronic device 100, such as controller 250. In the case of onboardcontrol, the amplitude and timing may be specified or modified by datacommands delivered from the pulse generator module 1406.

Other embodiments of electronic devices and tissue stimulation systemsare within the scope of the following claims.

What is claimed is:
 1. An implantable electronic device, comprising: aflexible circuit board; one or more circuit components attached to theflexible circuit board and configured to convert electrical energy intoelectrical pulses; and one or more electrodes attached to the flexiblecircuit board without cables connecting the electrodes to each other orto the flexible circuit board, the one or more electrodes configured toapply the electrical pulses to a tissue adjacent the implantableelectronic device.
 2. The implantable electronic device of claim 1,further comprising one or more joints at which the one or moreelectrodes are respectively attached to the flexible circuit board. 3.The implantable electronic device of claim 2, wherein the one or morejoints comprise one or more of stainless steel, platinum,platinum-iridium, gallium-nitride, titanium-nitride, and iridium-oxide.4. The implantable electronic device of claim 2, wherein the one or morejoints are part of the one or more electrodes.
 5. The implantableelectronic device of claim 2, wherein the one or more joints have athickness of about 0.05 mm to about 0.5 mm.
 6. The implantableelectronic device of claim 1, wherein the one or more electrodes areattached to the flexible circuit board respectively along one or moreinterior surfaces of the one or more electrodes.
 7. The implantableelectronic device of claim 6, wherein the one or more interior surfaceshave a shape that is complimentary to at least one or more portions ofthe one or more joints.
 8. The implantable electronic device of claim 1,wherein the one or more electrodes are attached to the flexible circuitboard respectively along one or more exterior surfaces of the one ormore electrodes.
 9. The implantable electronic device of claim 8,wherein the one or more exterior surfaces have a shape that iscomplimentary to at least one or more portions of the one or morejoints.
 10. The implantable electronic device of claim 1, wherein theone or more electrodes are attached to the flexible circuit board in anautomated manner.
 11. The implantable electronic device of claim 1,wherein the one or more electrodes are attached to the flexible circuitboard via laser welding, soldering, or conductive epoxy application. 12.The implantable electronic device of claim 1, wherein the one or moreelectrodes have a generally tubular shape.
 13. The implantableelectronic device of claim 1, wherein the one or more electrodes aredirectly attached to the flexible circuit board.
 14. The implantableelectronic device of claim 1, wherein the one or more electrodes areattached to the flexible circuit board within a compressive mechanicalstructure.
 15. The implantable electronic device of claim 1, furthercomprising an antenna attached to the flexible circuit board andconfigured to receive an input signal carrying the electrical energy.16. The implantable electronic device of claim 15, wherein the antennacomprises a layer of the flexible circuit board.
 17. The implantableelectronic device of claim 15, wherein the antenna is oriented parallelto the one or more circuits.
 18. The implantable electronic device ofclaim 15, wherein the antenna is oriented perpendicular to the one ormore circuits.
 19. The implantable electronic device of claim 15,wherein the antenna comprises two separate portions.
 20. The implantableelectronic device of claim 1, wherein the implantable electronic deviceis sized to be passed through an introducer needle.